1. Field of the Invention
The present invention relates to methods and apparatus for management and correction of spinal deformities, such as scoliosis.
2. Background Information
A serious deficiency presently exists with respect to conventional treatment and instrumentation for treating spinal deviation anomalies, such as scoliosis.
This circumstance presents a serious medical challenge, because scoliosis, other than mild to moderate cases, is a well-recognized health risk.
If scoliosis curvature exceeds 70 degrees, severe twisting of the spine occurs. This can cause the ribs to press against the lungs, restrict breathing, and reduce oxygen levels. The distortions may also affect the heart and possibly cause dangerous changes.
Eventually, if the curve reaches more than 100 degrees, both the lungs and the heart can be injured. Patients with this degree of severity are susceptible to lung infections and pneumonia. Curves greater than 100 degrees are associated with elevated mortality rates.
Present treatment regimens for scoliosis carry their own risks and side effects, which include:                Spinal fusion disease. Patients who are surgically treated with fusion techniques lose flexibility and may experience weakness in back muscles due to injuries during surgery.        Disk degeneration and low back pain. With disk degeneration, the disks between the vertebrae may become weakened and may rupture.        Height loss.        Lumbar flatback. This condition is most often the result of a scoliosis surgical procedure called the Harrington technique, used to eliminate lordosis (exaggeration of the inward curve in the lower back). Adult patients with flatback syndrome tend to stoop forward. They may experience fatigue and back pain and even neck pain.        Rotational trunk shift (uneven shoulders and hips).        
In some patients, years after the original surgery (particularly with the first generation of Harrington rods), the weight of the instrumentation can cause disk and joint degeneration severe enough to require surgery. Treatment may involve removal of the old instrumentation and extension of the fusion into the lower back.
Left untreated, or ineffectively treated, scoliosis carries long-term consequences.
Pain in adult-onset or untreated childhood scoliosis often develops because of posture problems that cause uneven stresses on the back, hips, shoulders, necks, and legs. Studies report, however, that patients with childhood scoliosis have the same incidence of back pain as the general population, which is very high (60% to 80%). In one study conducted 20 years after growth had stopped, two-thirds of adults who had lived with curvatures of 20 to 55 degrees reported back pain. In this study, most cases were mild, although other studies have reported that adults with a history of scoliosis tend to have chronic and more back pain than the general population.
Nearly all individuals with untreated scoliosis at some point develop spondylosis, an arthritic condition in the spine. The joints become inflamed, the cartilage that cushions the disks may thin, and bone spurs may develop. If the disk degenerates or the curvature progresses to the point that the spinal vertebrae begin pressing on the nerves, pain can be very severe and may require surgery. Even surgically treated patients are at risk for spondylosis if inflammation occurs in vertebrae around the fusion site.
The consequences of scoliosis are limited to the physical realm. The emotional impact of scoliosis, particularly on young girls or boys during their most vulnerable years, should not be underestimated. Adults who have had scoliosis and its treatments often recall significant social isolation and physical pain. Follow-up studies of children with scoliosis who did not have strong family and professional support often report significant behavioral problems.
Older people with a history of scoliosis, even those whose conditions were corrected, should realize that some negative emotional events in adulthood may possibly have their roots in their early experiences with scoliosis. Many studies have reported that patients who were treated for scoliosis have limited social activities and a poorer body image in adulthood. Some patients with a history of scoliosis have reported a slight negative effect on their sexual life. Pain appears to be only a minor reason for such limitation. An early Scandinavian study reported that adults with scoliosis had fewer job opportunities and a lower marriage rate than the general population.
It is clear, then, that scoliosis treatment options are presently lacking, and untreated scoliosis (except for mild to lower-moderate cases) is not an acceptable alternative.
There are many apparatus which are designed for attachment to, and positioning adjacent the spinal column, and in many instances, these apparatus are designed for use in treating spinal column anomalies, such as scoliosis. However, all known systems are limited by their design and known implementation modes on either arresting further deleterious rotation of the involved vertebrae, or fixing individual vertebrae once, by some means, they are brought to approximate a desired orientation and position.
Significant correction of severe scoliotic curvature to the point of approximating normal spinal configuration, particularly by a single process, is simply unknown in the art. This is, it is believed, the result of focus in the field on the positioning substantially seriatim of affected vertebrae. Applying derotational force to a vertebrae in this manner cannot effect en mass spinal reconfiguration without risking vertebral fracture at the point of spinal instrumentation fixation, particularly when using conventional instrumentation. Scoliosis has classically been regarded as principally a two dimensional deformity. Early methods of surgical correction have thus focused on two dimensional straightening of the classic S-shaped deformity. Over the last decade or so, more focus has been placed on the true three dimensional deformity. The third dimension is axial plane vertebral rotational deviation maximally affecting the apex of the scoliotic curve. A complete three dimensional correction has become the perceived goal of spine surgeons. There are no existing methods which consistently and reproducibly achieve this goal. Furthermore, significant, focused force applied to any individual vertebra risks spinal cord and related injury. Thus, only force which is inadequate to effect substantial correction to the entire spinal column is thus far ever applied, and correction of scoliotic curvatures are substantially limited.
It has become clear to the present inventor that desired levels of correction of spinal column anomalies, such as scoliosis, can only be achieved if the spinal column (or an affected segment thereof) is manipulated (or “derotated”) substantially as a whole into a desired configuration. To achieve such an objective, force must be applied safely to all to-be-derotated vertebrae, and the forces necessary to reconfigure all, or at least a substantial portion of the spinal column must be dispersed throughout the affected spinal segments or regions. Nothing in the prior art satisfies these requirements, either individually or in combination.